Four Seasons Miami (not on Miami Beach) is stay 2 nights - get 1 free - rooms starting at $250/night then (don't know your exact dates). So that's $166/night - and if there are 2 of you to a room - that's less than $100/night each including taxes. Really nice property (great pools) - and you can afford to rent a car/take cabs to South Beach if you'd like. Be a little flexible about where you stay - and you can get some really good deals at luxury properties. Robyn
P.S. FS Palm Beach has really good deals too.
P.P.S. You're talking prime hurricane season then - so keep your eyes open (or have a website bookmarked).